Just a simple batter rack. Good for keeping that junk drawer a little more organized. I also use this style of battery storage for all of my rechargeable batteries (including for cameras, etc.) that have constant cross-sections, or nearly. I like that I can quickly glance and see how many batteries I have charged/needing charged by keeping the charged ones always in the same orientation and vice-versa.
The author marked this model as their own original creation.